George's Island is the major island in the Boston Harbor Island National Recreation Area, a park comprised of 10 islands that is managed by a coalition of federal, state and city agencies. Accessible only by private boat or a 45-minute ferry ride from Long Wharf, this island features hiking trails, picnic areas and the remains of a Civil War-era fort. From here, a free water taxi can shuttle you to the other islands in the park. This island does have restrooms and a snack bar, but it's wise to bring provisions if you plan to island-hop. There are around 150 free events during the summer! Open daily from 9a.